1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to a digital transmitting and/or receiving apparatus and a method thereof, and more particularly, to a digital transmitting and/or receiving apparatus for simplifying structure of a receiving apparatus in a hierarchical modulation and demodulation system, and a method thereof.
2. Description of the Related Art
There has been increasing demands for higher transmission upgradability such as SD video, 5.1 channel audio, or 3D video, but also increasing concerns about deteriorating reception quality which is experienced when the signal transmission rate is increased. Accordingly, effort has been made to find a way to increase the resolution of a mobile broadcast.
As high efficiency media coding technique is developed, and higher efficiency modulation technique and channel coding technique are demanded, an improved system is needed, which can provide enhanced transmission resolution and better reception quality.
The hierarchical modulation and demodulation is considered to be a scheme that can provide both enhanced transmission resolution and reception quality. Since the hierarchical modulation and demodulation technique enables transmission of both high and low resolution signals, a receiving end with better reception condition receives high resolution signal, while a receiving end with lower reception condition can receive low resolution signal.
Therefore, with the hierarchical modulation and demodulation technique, high resolution signal is received under a good reception condition, and low resolution signal instead of high resolution signal is received under a poor reception condition, thereby preventing interruption of broadcast.
However, the hierarchical modulation and demodulation system has shortcomings. That is, it is necessary to employ forward error correctors (FEC) for high and low resolution signals, respectively. This means complicated structure at a receiving end, and an increased amount of algorithms and subsequently increasing power consumption of a mobile device.